397 lines
12 KiB
C++
397 lines
12 KiB
C++
/***************************************************************************
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* Copyright (C) 2009 by Stefan Bühler *
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* stbuehler@web.de *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
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***************************************************************************/
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#include "toruschess.h"
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namespace toruschess {
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QString state2string(GameState state) {
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switch (state) {
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case TURN_WHITE: return "White's turn";
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case TURN_BLACK: return "Black's turn";
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case WON_WHITE: return "White is the winner";
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case WON_BLACK: return "Black is the winner";
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case DRAW: return "Draw game";
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}
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return "Invalid GameState";
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}
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Move::Move(const Field* field, const Pos &from, const Pos &to)
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: m_from(from), m_to(to), m_prevFrom(field->place(from)), m_prevTo(field->place(to)), m_player(field->player(from)) { }
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Move::Move()
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: m_from(), m_to(), m_prevFrom(0), m_prevTo(0), m_player(NOPLAYER) { }
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static const int start_field[8][8] = {
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{ -KNIGHT, -PAWN, -ROOK, 0, 0, 0, 0, 0 },
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{ -BISHOP, -KING, -QUEEN, 0, 0, 0, 0, 0 },
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{ -ROOK, -PAWN, -KNIGHT, 0, 0, 0, 0, 0 },
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{ 0, 0, 0, 0, 0, 0, 0, 0 },
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{ 0, 0, 0, 0, ROOK, PAWN, KNIGHT, 0 },
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{ 0, 0, 0, 0, QUEEN, KING, BISHOP, 0 },
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{ 0, 0, 0, 0, KNIGHT, PAWN, ROOK, 0 },
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{ 0, 0, 0, 0, 0, 0, 0, 0 }
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};
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Field::Field()
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: m_wking(5, 5), m_bking(1, 1) {
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memcpy(m_places, start_field, sizeof(start_field));
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}
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void Field::reset() {
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m_wking = Pos(5, 5);
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m_bking = Pos(1, 1);
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memcpy(m_places, start_field, sizeof(start_field));
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}
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void tryDirection(QList<Move> &moves, const Field *field, int thePlace, const Pos &from, int dx, int dy) {
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for (int d = 1; d < 8; d++) {
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Pos to = Pos(from.x() + d*dx, from.y() + d*dy);
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int toPlace = field->place(to);
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if (0 == toPlace) {
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// qDebug("move 1, %i", d);
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moves.push_back(Move(field, from, to)); /* move */
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} else {
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if (0 > toPlace * thePlace) {
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// qDebug("beat 1, %i", d);
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moves.push_back(Move(field, from, to)); /* beat */
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} else {
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// qDebug("hit friend, %i", d);
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}
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for (int c = 7; c > d; c--) {
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to = Pos(from.x() + c*dx, from.y() + c*dy);
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toPlace = field->place(to);
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if (0 == toPlace) {
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// qDebug("move 2, %i %i", d, c);
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moves.push_back(Move(field, from, to)); /* move */
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} else if (0 > toPlace * thePlace) {
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// qDebug("beat 2, %i %i", d, c);
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moves.push_back(Move(field, from, to)); /* beat */
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break;
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} else {
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// qDebug("hit friend, %i %i, (%i, %i) = %i", d, c, to.x(), to.y(), toPlace);
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break;
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}
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}
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break;
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}
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}
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}
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/* 7 == -1 mod 8, 6 == -2: but positive values are needed for (a + b) % 8 >= 0 */
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typedef struct { int x, y; } move_delta;
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static const move_delta moves_pawn_walk[4] = { { 1, 0 }, { 0, 1 }, { 7, 0 }, { 0, 7 } };
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static const move_delta moves_pawn_beat[4] = { { 1, 1 }, { 1, 7 }, { 7, 7 }, { 7, 1 } };
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static const move_delta moves_knight[8] = { { 1, 2 }, { 1, 6 }, { 7, 2 }, { 7, 6 }, { 2, 1 }, { 2, 7 }, { 6, 1 }, { 6, 7 } };
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static const move_delta moves_king[8] = { { 1, 1 }, { 1, 0 }, { 1, 7 }, { 0, 7 }, { 7, 7 }, { 7, 0 }, { 7, 1 }, { 0, 1 } };
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static Pos operator + (const Pos &p, move_delta d) {
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return Pos(p.x() + d.x, p.y() + d.y);
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}
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QList<Move> Field::simpleValidMoves(const Pos &from) const {
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QList<Move> moves;
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int thePlace = place(from);
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Piece thePiece = place2piece(thePlace);
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// qDebug("simpleValidMoves: %i", thePiece);
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switch (thePiece) {
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case NOPIECE:
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break;
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case PAWN:
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for (int i = 0; i < 4; i++) {
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if (0 == place(from + moves_pawn_walk[i])) {
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moves.push_back(Move(this, from, from + moves_pawn_walk[i]));
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}
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if (0 > thePlace * place(from + moves_pawn_beat[i])) {
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moves.push_back(Move(this, from, from + moves_pawn_beat[i]));
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}
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}
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break;
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case KNIGHT:
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for (int i = 0; i < 8; i++) {
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if (0 >= thePlace * place(from + moves_knight[i])) {
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moves.push_back(Move(this, from, from + moves_knight[i]));
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}
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}
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break;
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case BISHOP:
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tryDirection(moves, this, thePlace, from, 1, 1);
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tryDirection(moves, this, thePlace, from, 1, 7);
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break;
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case ROOK:
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tryDirection(moves, this, thePlace, from, 1, 0);
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tryDirection(moves, this, thePlace, from, 0, 1);
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break;
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case QUEEN:
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tryDirection(moves, this, thePlace, from, 1, 1);
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tryDirection(moves, this, thePlace, from, 1, 7);
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tryDirection(moves, this, thePlace, from, 1, 0);
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tryDirection(moves, this, thePlace, from, 0, 1);
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break;
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case KING:
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for (int i = 0; i < 8; i++) {
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if (0 >= thePlace * place(from + moves_king[i])) {
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moves.push_back(Move(this, from, from + moves_king[i]));
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}
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}
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break;
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}
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// qDebug("simpleValidMoves: found %i", moves.size());
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return moves;
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}
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QList<Move> Field::validMoves(const Pos &from) const {
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QList<Move> moves = simpleValidMoves(from);
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QList<Move> resMoves;
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Field testField(*this);
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Player pl = player(from);
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foreach(Move m, moves) {
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Q_ASSERT(validMove(m));
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testField.move_unchecked(m);
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if (!testField.inCheck(pl)) {
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resMoves.push_back(m);
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}
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testField.undo_unchecked(m);
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}
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return resMoves;
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}
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static bool checkReach(const Field *field, const Pos &from, const Pos &dest, int dx, int dy) {
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for (int d = 1; d < 8; d++) {
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Pos to = Pos(from.x() + d*dx, from.y() + d*dy);
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if (dest == to) return true;
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int toPlace = field->place(to);
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if (0 == toPlace) {
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continue;
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} else {
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for (int c = 7; c > d; c--) {
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to = Pos(from.x() + c*dx, from.y() + c*dy);
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if (dest == to) return true;
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toPlace = field->place(to);
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if (0 == toPlace) {
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continue;
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} else {
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return false;
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}
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}
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return false;
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}
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}
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return false;
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}
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bool Field::validMove(const Move &m) const {
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if (player(m.from()) != m.player()) return false;
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if (m.player() == NOPLAYER) return false;
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if (place(m.from()) != m.prevFrom() || place(m.to()) != m.prevTo()) return false;
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if (player(m.to()) == m.player()) return false;
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switch (piece(m.from())) {
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case NOPIECE:
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return false;
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case PAWN: {
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int dx = (8 + m.from().x() - m.to().x()) % 8, dy = (8 + m.from().y() - m.to().y()) % 8;
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if ((dx > 1 && dx < 7) || (dy > 1 && dy < 7)) return false;
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if (dx != 0 && dy != 0) return player(m.to()) != NOPLAYER; /* beat */
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return player(m.to()) == NOPLAYER; /* walk */
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}
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case KNIGHT: {
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int dx = (8 + m.from().x() - m.to().x()) % 8, dy = (8 + m.from().y() - m.to().y()) % 8;
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return ((dx == 2 || dx == 6) && (dy == 1 || dy == 7)) || ((dx == 1 || dx == 7) && (dy == 2 || dy == 6));
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}
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case BISHOP: {
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int dx = (8 + m.from().x() - m.to().x()) % 8, dy = (8 + m.from().y() - m.to().y()) % 8;
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if (dx == dy) {
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if (dx == 4) {
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return checkReach(this, m.from(), m.to(), 1, 1) || checkReach(this, m.from(), m.to(), 1, 7);
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} else {
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return checkReach(this, m.from(), m.to(), 1, 1);
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}
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} else if (dx + dy == 8) {
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return checkReach(this, m.from(), m.to(), 1, 7);
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} else {
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return false;
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}
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}
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case ROOK: {
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int dx = (8 + m.from().x() - m.to().x()) % 8, dy = (8 + m.from().y() - m.to().y()) % 8;
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if (dy == 0) {
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return checkReach(this, m.from(), m.to(), 1, 0);
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} else if (dx == 0) {
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return checkReach(this, m.from(), m.to(), 0, 1);
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} else {
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return false;
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}
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}
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case QUEEN: {
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int dx = (8 + m.from().x() - m.to().x()) % 8, dy = (8 + m.from().y() - m.to().y()) % 8;
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if (dx == dy) {
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if (dx == 4) {
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return checkReach(this, m.from(), m.to(), 1, 1) || checkReach(this, m.from(), m.to(), 1, 7);
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} else {
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return checkReach(this, m.from(), m.to(), 1, 1);
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}
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} else if (dx + dy == 8) {
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return checkReach(this, m.from(), m.to(), 1, 7);
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} else if (dy == 0) {
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return checkReach(this, m.from(), m.to(), 1, 0);
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} else if (dx == 0) {
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return checkReach(this, m.from(), m.to(), 0, 1);
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} else {
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return false;
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}
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}
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case KING: {
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int dx = (8 + m.from().x() - m.to().x()) % 8, dy = (8 + m.from().y() - m.to().y()) % 8;
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if ((dx > 1 && dx < 7) || (dy > 1 && dy < 7)) return false;
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return true;
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}
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}
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return false;
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}
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void Field::move_unchecked(const Move &m) {
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place(m.from()) = 0;
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place(m.to()) = m.prevFrom();
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if (m.prevFrom() == KING) {
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m_wking = m.to();
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} else if (m.prevFrom() == -KING) {
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m_bking = m.to();
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}
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}
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void Field::undo_unchecked(const Move &m) {
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place(m.from()) = m.prevFrom();
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place(m.to()) = m.prevTo();
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if (m.prevFrom() == KING) {
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m_wking = m.from();
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} else if (m.prevFrom() == -KING) {
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m_bking = m.from();
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}
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}
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bool Field::move(const Move &m) {
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if (!m.valid()) return false;
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if (!validMove(m)) return false;
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move_unchecked(m);
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if (inCheck(m.player())) {
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undo_unchecked(m);
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return false;
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}
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return true;
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}
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bool Field::undo(const Move &m) {
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if (place(m.from()) != 0 || place(m.to()) != m.prevFrom()) return false;
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undo_unchecked(m);
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return true;
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}
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bool Field::inCheck(Player player, const Pos &pking) const {
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for (int x = 0; x < 8; x++) for (int y = 0; y < 8; y++) {
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Pos curp(x, y);
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if (0 > place(curp) * player && validMove(Move(this, curp, pking))) {
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return true;
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}
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}
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return false;
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}
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bool Field::inCheck(Player p) const {
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const Pos &pos = (p == WHITE) ? m_wking : m_bking;
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if (player(pos) != p || piece(pos) != KING) return false;
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return inCheck(p, pos);
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}
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Game::Game(QObject *parent)
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: QObject(parent), m_field(new Field()), m_state(TURN_WHITE) { }
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Game::~Game() {
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delete m_field;
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}
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bool Game::move(const Move &m) {
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if (!m.valid()) return false;
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switch (m_state) {
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case TURN_WHITE:
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if (m.player() != WHITE) return false;
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break;
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case TURN_BLACK:
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if (m.player() != BLACK) return false;
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break;
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default:
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return false;
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}
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if (m_field->move(m)) {
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m_moves.push_back(m);
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if (m_state == TURN_WHITE) {
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m_state = TURN_BLACK;
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if (possibleMoves().empty()) {
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if (m_field->inCheck(BLACK)) {
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m_state = WON_WHITE;
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} else {
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m_state = DRAW;
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}
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}
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} else {
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m_state = TURN_WHITE;
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if (possibleMoves().empty()) {
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if (m_field->inCheck(WHITE)) {
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m_state = WON_BLACK;
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} else {
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m_state = DRAW;
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}
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}
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}
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emit moved(m);
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emit changed(m_state);
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emit updated();
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return true;
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}
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return false;
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}
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void Game::restart() {
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m_state = TURN_WHITE;
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m_field->reset();
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emit changed(m_state);
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emit started();
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emit updated();
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}
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QList<Move> Game::possibleMoves() const {
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Player player = NOPLAYER;
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switch (m_state) {
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case TURN_WHITE:
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player = WHITE;
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break;
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case TURN_BLACK:
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player = BLACK;
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break;
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default:
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return QList<Move>();
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}
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QList<Move> moves;
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for (int x = 0; x < 8; x++) for (int y = 0; y < 8; y++) {
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Pos curp(x, y);
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if (0 < m_field->place(curp) * player)
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moves += m_field->validMoves(curp);
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}
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return moves;
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}
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}
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